Benzopyrans

About: Benzopyrans is a research topic. Over the lifetime, 694 publications have been published within this topic receiving 8830 citations.

Synthesis and screening of 1, 3, 4-oxadiazinoindolinone and s-triazole derivatives of pyranobenzopyran

Abstract: 3-Formyl-4- hydroxycoumarin is treated with malonic acid in the presence of zinc chloride catalyst to give 2H, 5H-2,5-dioxo-3-pyrano[3, 2-c]benzopyranoic acids la-d which on treatment with methanol in the presence of thionyl chloride give methyl 2H, 5H-2,5-dioxopyrano[3, 2-c]benzopyran-3-oates 2a-d. Compounds 2a-d were converted into their acid hydrazides 3a-d. 3a-d on treatment with isatin yield IH, 2H-3-(2H, 5H-2,5-dioxopyrano[3, 2-c]benzopyran-3-carboxyhydrazono)-2-indolinones 4a-d which on cyclisation with conc. H 2 SO 4 afford 3-[1, 3, 4-oxadiazino[5, 6-b]indol-2-yl]-2,5-dioxopyrano[3,2-c]benzopyrans 5a-d. Acid hydrazides 3a-d on treatment with carbon disulfide in 10% KOH at room temperature followed by treatment with ortho-chlorobenzoic acid hydrazide furnish 3-(2H, 5H-2, 5-dioxopyrano[3, 2-c]benzopyran-3-yl)-4-{N-2'-chlorophenylcarboxamido]-5-mercapto-1,2,4-triazoles 6a-d.

Six‐Membered Ring Systems: With O and/or S Atoms

Abstract: The review covers work published in the calendar year 2010. Novel reaction chemistry and new ring synthetic methods for pyrans, [1]benzopyrans, dihydro[1]benzopyrans (chromenes, chromans), [2]benzopyrans, dihydro[2]benzopyrans (isochromenes, isochromans), pyranones, coumarins, chromones, xanthenes, xanthones, thiopyrans, dioxins. dioxanes, trioxanes, tetraoxanes, dithianes, trithianes, oxathianes are reviewed.

Des-A steroidal intermediates

Abstract: Stereo-specific total synthesis of steroidal materials. 7Substituted 3-oxo-1-heptenes or variants thereof are reacted with 2-alkylcycloalkane-1,3-diones yielding 3-substituted 6a Beta alkyl-cyclopenta (f)(1)benzopyrans or naphtho (2,1-b)pyrans. These are then subjected to a selective catalytic hydrogenation followed by an introduction of a hydroxy, alkoxy or acyloxy group at the 4a-position to produce a 3-substituted 6a Beta ,4ahydroxy, alkoxy or acyloxy perhydrocyclopenta (f)(1)benzopyran or perhydro-naphtho (2,1-b) pyran. These latter compounds are then converted into 4- or 5-(3-oxoalkyl)perhydroindene-5-ones or perhydronaphthalene-6-ones which in turn can be converted to known steroidal materials by known methods.

Diels—Alder Reaction of 2-Nitro Glycals: A New Route to the Synthesis of Benzopyrans.

Abstract: Synthesis of different benzopyrans was achieved by Diels-Alder reaction of 2-nitro glycals with Danishefky's diene, hydrolysis of the enol ether moiety, and subsequent elimination of the nitro and methoxy group